Grlnding-machine



A. SCRIVENOR.

GRINDING MACHINE.

APPLHLAHON FILED NOV. I3. 1911.

Patented Aug. 26, 1919.

3 SHEET SHEET 1.

FLq I A. SCRIVENOR.

GRINDING MACHINE.

APPLICATION HLED NOV-13.1917. 1,314,154. Patented Aug. 26, 1919.

3 SHEETS-SHEET 2- FL qlll.

gnucuhm A. SCRIVENOR GRINDING MACHINE.

APPLICATION FILED NOV. 13. 1911.

Patented Aug. 26, 1919.

3 SHEETS SHEET 3- ARTHUR SCRIVENOR, 0F RICHMOND, VIRGINIA.

GRIN DIN G-MACHIN E.

Specification of Letters Patent.

, Patented Aug. 26, 1919.

Application filed November 13, 1917. Serial No. 202,621.

To all whom it may concern Be it known that I, ARTHUR SCRIVENOR, acitizen of the United States, residing at Richmond, in the county ofHenrico and State of Vir inia, have invented certain new and usefulImprovements in Grinding-Machines, of which the following'is aspamfication.

My invention relates to machines for grinding cutting tools ofcylindrical shape, and is described as used for grinding the threads orteeth of steel burs used in dressing grind-stones; but it is not limitedto such use.

The threads of steel burs may be straight or parallel with the axis ofthe bur, diagonal to the axis of the bur, or spirally arranged on theface of the bur. Combinations of these forms of thread are usedto formdiamond-point, chisel-point, and other 1nterrupted forms of thread. Inanother application, filed on May 9, 1917, Serial No. 167,578, I havedescribed a machine for grinding the spiral threads of burs. In thepresent application a machine or attachment for grinding straightthreads or dlagonal threads, and also straight and diagonal1nterruptions on spiral threads is descrlbed; and the object of thisinvention is to provlde a machine whereby the said grinding may beaccomplished with accuracy, and rapidly.

Though these two machines are described and claimed in separateapplications, 1n practice it is convenient to incorporate them in onemachine, as illustrated in the drawings of the application filed May 9,1917, on the machine for grinding spiral threads referred to above.

In the drawings accompanying and forming a part of this specification,and in which like numerals refer to like parts in the sev eralviews,Figure I shows the machine in side elevation; Fig. II in endelevatlon, and Fig. III in plan. Fig. IV illustrates the abrasive wheelstand, and Fig. V illustrates the table on which the abrasive wheel isadjusted for cutting straight or diagonal burs. Fig. VI is a verticallongitudinal section of the machine, and *ig. VII is an end View of thesame with the casing in section to show the mechanism within. Fig. VIIIis a detail of the indexing wheel shown in Fig. VI.

()n a table 100 is carried the grinding wheel 110, mounted on a shaftwhich may be driven by pulleys and belts from overhead lincs, or bymeans of an electric motor,

'The motor 111 as shown at 111 in Figs. I, II, and III. is preferablymounted on a bracket 112 which is pivoted on the table 100 at a pointexactly beneath the center of the abrasive wheel 110. In Fig. III thebracket 112 is shown pivoted at 113. See also Fig. V. The motor bracket112 is secured to the table 100 by means of bolts passed through theslots in the foot of the bracket and through one or other of the holes117, 118 and 119 in the top of the table.

Referring to I, II, III and VI, straight and diagonal cut teeth areground on work supported on the spindle 150. The spindle 150 is carriedin bearings mounted in the housing 151, which bearings permit rotationof the spindle, a thrust bearing being added to prevent GDClWlSBDlOtiODof the spindle relative to the housing.

Near the farther end of the spindle 150 is mounted a cylindrical cam152, 1n which are cut a straight roller path and diagonal paths havingthe same lead as the diagonal bur threads to be ground. At the extremeend of the spindle 150 is shown an indexing wheel 153 for use in settingthe several threads of a bur successively in position for grinding. Forfine setting I use the worm and gear adjustment shown in Figs. VI andVII in which 15-1 is a worm wheel rigidly secured to the spindle 150,and 155 is a worm cut on a shaft 156v having a milled head 157, andmounted in bearings 158, 159, which bearings are secured to the frame ofthe cam 152. In a bracket 160 to one side of the cam 152 is adjustablymounted a pin 161, carrying a roller 162, the said roller )eing mountedon the pin 161 by means of a small annular ball bearing to prevent wearof the pin or of the bore in the roller. If the roller be of small size,so that a larger number of slots may be used on one cam, the outer raceof the ball bearing may be used as the cam roller. Such use alsosimplifies construction, and reduces the number of parts. The roller 162and pin 161 are held in position by means of a set screw 163. The roller162 may be withdrawn from the slot in the cam by merely slacking the setscrew, and

prevented from rotating by the cam roller 162, and the worm wheel ispinned or keyed to the spindle; consequently the turning of the worm 155revolves the spindle 150, and

the work carried by it. This arrangement handle 170. When the handle isoperated to oscillate the shaft 169, the sector'168 engaging the rack167 imparts to the slide 164:,

and consequently to the work carried by the spindle 150, a reciprocatingmotion in a horizontal plane. The movement of the slide 164:. is limitedby stops 171 and 172, secured to the walls of the bracket 166, whichstops limit the motion of the sector 168. I

The bracket 160, carrying the pin 161 and cam roller 162, is attached tothe bracket 166. If the roller 162 is in the straight slot of the camwhen the handle 170 is actuated, the spindle and work will have only areciprocating motion. But if the roller 162 is engaging in one of thediagonal slots on the cam 152, when the handle 170 is actuated the workwill be given a reciprocating combined with a rotary motion; and anypoint on the work will follow a path similar to the path of the slot onthe cam 152 in which the roller 162 is engaging. So, to provide forthegrinding of a thread of any practicable inclination to the axis it isonly necessary to provide a slot of like inclination on the cam 152. Thepractical limit to such inclination is that at which the frictionbetween the roller and the cam path becomes too great for smooth andfree movement of the cam.

The front of the bracket 166 is slidably mounted in slots in a block173. The block is also slida bly mounted on ways carried by the table100, and is adjustable in a vertical direction by means of the screwgear 174: operated by the hand wheel 175, and working in a fixed nut 176carried by the bracket 177 bolted to the table 100. When the height ofthe block 173 is so adjusted, so also is the height of the bracket 166,and consequently of the work spindle 150, so that the work may beproperly presented to the abrasive wheel. This wheel is shown in Fig.HT, ar-

ranged to grind a thread inclined at an angle of 45 degrees to the axisof the work.

Assuming that the abrasive wheel is in position and that the work is atthe proper height and the thread to be ground correctly set, a forwardmovement of the handle 17 0 will cause the thread to be brought intoenparts,for instance, the roller 162 and cam slot, the teeth of the rack167 and sector 168,-would have the effect of changing the setting of aninclined work thread, and a spoiled thread would be likely to result. I

therefore provide means for quickly bringing the work thread out ofcontact with the abrasive wheel before the return stroke, and

whereby may be again quickly brought into position for engagement beforethe next forward stroke, and without disturbing the vertical adjustmentof the block 17 3, as follows:

Journaled in bearings 180 in the block 17 3 (see Fig. VI) is a shaft 181provided at one end with a handle 182. Pinned to the shaft 181 is thelower end of a toggle 183, jointed at 184, and the upper end 185 ofwhich is mounted on a short shaft or pin 186 journaled in bearings 187attached to the sides of the bracket 166.. Stops for the motion of thetoggle are attached to the bracket 166 at 188 and 189. The toggle shaft181 is not in contact with the bracket 166; but passes through elongatedopenings 190 in the sides of the bracket. In Fig. VI the toggle is shownin its extended position, and bearing against the stop 188. Comparedwith the position of the block 173, the bracket 166 is now in itshighest position. Remembering that the height of the shaft 181 is fixed(relatively to the height of the block 17 3), if the handle 182 be now,operated to throw the toggle joint 184 against the stop 189, thedistance between the centers of the shafts 181 and 186 will be reduced,and by the amount of this reduction will the shaft 186 and the bracket166 be lowered. This amount may be arranged to suit the work in hand bymaking the stop 189 of the proper length. I have found that a drop offrom to is'suflicient. The control of the work spindle is now as follows:-The block 173 carrying the bracket 166 having been adjusted to theproper height, and the handle 170 pulled back to bring the sector 168against the stop 171, the handle 182 is then pulled back, extending thetoggle183. Holding back the handle 182, the handle 170 is carriedforward, bringing the work thread 7 then carried forward, throwing thetoggle joint 184 against the stop 189, lowering bracket 166, andlowering the work from engagement with the abrasive wheel. The handle170 is thenpulled back to its rearward position; and the work is set forthe grinding of the next thread. Pulling back the handle 182 to againraise the work, the grinding operation is repeated.

Referring again to Fig. VI, the indexing wheel 153 is removably mountedon the extended hub of the worm gear 154, and clamped thereon by the nut192. A number of indexing wheels may be employed where the range of workto be ground is large. Preferably these indexing wheels are notched onthe periphery, and engaging in the notches is a spring finger 191, (seeFig. VIII), attached to the slide 164. By means of the worm gearing 154,155, the notches of the indexing wheel are accurately set againstthe'finger 191, so indexing the work, and without disturbing the cam 152through the axis of which the spindle 150 is free to revolve. So long asthe roller 162 engages a path of the cam. 152 the worm gearing 151, 155,forms an effective lock for the spindle 150, holding it in positionsubject to the control of the movement of the slide 161 and the slots ofthe cam 152.

I have described my machine as arranged for grinding bur and similarthreads; but it can with advantage be used for grinding other articlesin which precision is required.

In the claims I have referred to the rectilinear motion of the workspindle as the advance, for the sake of brevity, and it is to beunderstood that by advance I refer to motion in line with the axis ineither direction, toward or from the grinding wheel.

I claim 1. The combination of a spindle rotatably mounted in bearings,means for securing the work to the spindle, a cylindrical cam rotatablymounted on and concentric with the spindle, a fixed roller adapted toengage a path on the cam, a worm mounted on the cam body, and a wormwheel mounted axially and rigidly on the spindle and engaging the worm.

2. The combination of a spindle mounted in bearings, a cylindrical camaxially mounted on the spindle, a fixed roller engaging a path of thecam, a worm mounted on the cam loody, and a worm wheel axially andrigidly mounted on the spindle, and engaging the worm.

3. The combination of a spindle mounted in bearings, means for securingwork to the spindle, an indexing wheel fixed on the spindle, a stopadapted to engage in a notch on the index wheel, a worm wheel fixed onthe spindle, a fixed worm engaging in the worm wheel, and adapted whenrevolved to revolve the worm wheel and with it the spindle to index thework.

4. The combination of a spindle mounted in bearings, means for securingwork to the spindle, a platen carrying the s indle bearings, means forimparting to tie platen a forward movement and a backward movement,means for adjusting the vertical position of the platen, a secondadjusting means whereby the platen may be lowered and raised again toits original position without disturbing the adjustment of the firstadjusting means.

5. The combination of a table, an abrasive Wheelmounted on the table, ablock vertically adjustable with reference to the table, means foradjusting the block, a bracket vertically adjustable on the block, meansfor adjusting the bracket, a platen mounted on the bracket and adaptedto reciprocate on the bracket, means for reciprocating the platen, awork holder mounted on the platen, and means for securing the work tothe work holder.

6. The combination of a table, dressing means mounted on the table, awork holder, means for bringing the work into engagement with, and forwithdrawing it from, the dressing means, means for adjusting thevertical height of the work with reference to the dressing means, and asecond adjustingmeans for changing the vertical height of the work tobring it into and out of engagcment with the dressing means.

7. The combination of means for dressing the work, means for supportingthe work, a toggle mounted at one end on a fixed hearing and having itsother end pivoted to the work supporting means and so arranged that whenoperated the work is brought into ongagement with or out of engagementwith the dressing means, and means for operating the toggle.

8. The combination of means for dressing the work, means for supportingthe work, means for reciprocating the work in a horizontal plane intoand out of engagement with the dressing means, means for controlling theposition of the work in a horizontal plane with reference to thedressing means, and means for adjusting the position of the work in avertical plane and adapted to bring it into and out of engagement withthe dressing means.

In testimony whereof I affix my signature, in presence of two witnesses.

ARTHUR SCRIVENOR. Witnesses:

M. E. MALONE, A. L. CAMPBELL.

